Problem: Evaluate the following expression when $b = 6$ and $a = 7$. $9$ $b$ $ + 7$ $a$ $ + 7$
Answer: Substitute $6$ for ${b}$ and $7$ for ${a}$ $ = 9{(6)} + 7{(7)} + 7 $ $ = 54 + 49 + 7 $ $ = 110$